kernel/time/timer_list.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * List pending timers
   4  *
   5  * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
   6  */
   7
   8 #include <linux/proc_fs.h>
   9 #include <linux/module.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/sched.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/kallsyms.h>
  14 #include <linux/nmi.h>
  15
  16 #include <linux/uaccess.h>
  17
  18 #include "tick-internal.h"
  19
  20 struct timer_list_iter {
  21         int cpu;
  22         bool second_pass;
  23         u64 now;
  24 };
  25
  26 /*
  27  * This allows printing both to /proc/timer_list and
  28  * to the console (on SysRq-Q):
  29  */
  30 __printf(2, 3)
  31 static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
  32 {
  33         va_list args;
  34
  35         va_start(args, fmt);
  36
  37         if (m)
  38                 seq_vprintf(m, fmt, args);
  39         else
  40                 vprintk(fmt, args);
  41
  42         va_end(args);
  43 }
  44
  45 static void
  46 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
  47             int idx, u64 now)
  48 {
  49         SEQ_printf(m, " #%d: <%pK>, %ps", idx, taddr, timer->function);
  50         SEQ_printf(m, ", S:%02x", timer->state);
  51         SEQ_printf(m, "\n");
  52         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  53                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  54                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  55                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  56                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  57 }
  58
  59 static void
  60 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  61                     u64 now)
  62 {
  63         struct hrtimer *timer, tmp;
  64         unsigned long next = 0, i;
  65         struct timerqueue_node *curr;
  66         unsigned long flags;
  67
  68 next_one:
  69         i = 0;
  70
  71         touch_nmi_watchdog();
  72
  73         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
  74
  75         curr = timerqueue_getnext(&base->active);
  76         /*
  77          * Crude but we have to do this O(N*N) thing, because
  78          * we have to unlock the base when printing:
  79          */
  80         while (curr && i < next) {
  81                 curr = timerqueue_iterate_next(curr);
  82                 i++;
  83         }
  84
  85         if (curr) {
  86
  87                 timer = container_of(curr, struct hrtimer, node);
  88                 tmp = *timer;
  89                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
  90
  91                 print_timer(m, timer, &tmp, i, now);
  92                 next++;
  93                 goto next_one;
  94         }
  95         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
  96 }
  97
  98 static void
  99 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 100 {
 101         SEQ_printf(m, "  .base:       %pK\n", base);
 102         SEQ_printf(m, "  .index:      %d\n", base->index);
 103
 104         SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
 105
 106         SEQ_printf(m,   "  .get_time:   %ps\n", base->get_time);
 107 #ifdef CONFIG_HIGH_RES_TIMERS
 108         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 109                    (unsigned long long) ktime_to_ns(base->offset));
 110 #endif
 111         SEQ_printf(m,   "active timers:\n");
 112         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 113 }
 114
 115 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 116 {
 117         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 118         int i;
 119
 120         SEQ_printf(m, "cpu: %d\n", cpu);
 121         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 122                 SEQ_printf(m, " clock %d:\n", i);
 123                 print_base(m, cpu_base->clock_base + i, now);
 124         }
 125 #define P(x) \
 126         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 127                    (unsigned long long)(cpu_base->x))
 128 #define P_ns(x) \
 129         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 130                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 131
 132 #ifdef CONFIG_HIGH_RES_TIMERS
 133         P_ns(expires_next);
 134         P(hres_active);
 135         P(nr_events);
 136         P(nr_retries);
 137         P(nr_hangs);
 138         P(max_hang_time);
 139 #endif
 140 #undef P
 141 #undef P_ns
 142
 143 #ifdef CONFIG_TICK_ONESHOT
 144 # define P(x) \
 145         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 146                    (unsigned long long)(ts->x))
 147 # define P_ns(x) \
 148         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 149                    (unsigned long long)(ktime_to_ns(ts->x)))
 150         {
 151                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 152                 P(nohz_mode);
 153                 P_ns(last_tick);
 154                 P(tick_stopped);
 155                 P(idle_jiffies);
 156                 P(idle_calls);
 157                 P(idle_sleeps);
 158                 P_ns(idle_entrytime);
 159                 P_ns(idle_waketime);
 160                 P_ns(idle_exittime);
 161                 P_ns(idle_sleeptime);
 162                 P_ns(iowait_sleeptime);
 163                 P(last_jiffies);
 164                 P(next_timer);
 165                 P_ns(idle_expires);
 166                 SEQ_printf(m, "jiffies: %Lu\n",
 167                            (unsigned long long)jiffies);
 168         }
 169 #endif
 170
 171 #undef P
 172 #undef P_ns
 173         SEQ_printf(m, "\n");
 174 }
 175
 176 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 177 static void
 178 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 179 {
 180         struct clock_event_device *dev = td->evtdev;
 181
 182         touch_nmi_watchdog();
 183
 184         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 185         if (cpu < 0)
 186                 SEQ_printf(m, "Broadcast device\n");
 187         else
 188                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 189
 190         SEQ_printf(m, "Clock Event Device: ");
 191         if (!dev) {
 192                 SEQ_printf(m, "<NULL>\n");
 193                 return;
 194         }
 195         SEQ_printf(m, "%s\n", dev->name);
 196         SEQ_printf(m, " max_delta_ns:   %llu\n",
 197                    (unsigned long long) dev->max_delta_ns);
 198         SEQ_printf(m, " min_delta_ns:   %llu\n",
 199                    (unsigned long long) dev->min_delta_ns);
 200         SEQ_printf(m, " mult:           %u\n", dev->mult);
 201         SEQ_printf(m, " shift:          %u\n", dev->shift);
 202         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 203         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 204                    (unsigned long long) ktime_to_ns(dev->next_event));
 205
 206         SEQ_printf(m, " set_next_event: %ps\n", dev->set_next_event);
 207
 208         if (dev->set_state_shutdown)
 209                 SEQ_printf(m, " shutdown:       %ps\n",
 210                         dev->set_state_shutdown);
 211
 212         if (dev->set_state_periodic)
 213                 SEQ_printf(m, " periodic:       %ps\n",
 214                         dev->set_state_periodic);
 215
 216         if (dev->set_state_oneshot)
 217                 SEQ_printf(m, " oneshot:        %ps\n",
 218                         dev->set_state_oneshot);
 219
 220         if (dev->set_state_oneshot_stopped)
 221                 SEQ_printf(m, " oneshot stopped: %ps\n",
 222                         dev->set_state_oneshot_stopped);
 223
 224         if (dev->tick_resume)
 225                 SEQ_printf(m, " resume:         %ps\n",
 226                         dev->tick_resume);
 227
 228         SEQ_printf(m, " event_handler:  %ps\n", dev->event_handler);
 229         SEQ_printf(m, "\n");
 230         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 231
 232 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 233         if (cpu >= 0) {
 234                 const struct clock_event_device *wd = tick_get_wakeup_device(cpu);
 235
 236                 SEQ_printf(m, "Wakeup Device: %s\n", wd ? wd->name : "<NULL>");
 237         }
 238 #endif
 239         SEQ_printf(m, "\n");
 240 }
 241
 242 static void timer_list_show_tickdevices_header(struct seq_file *m)
 243 {
 244 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 245         print_tickdevice(m, tick_get_broadcast_device(), -1);
 246         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 247                    cpumask_pr_args(tick_get_broadcast_mask()));
 248 #ifdef CONFIG_TICK_ONESHOT
 249         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 250                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 251 #endif
 252         SEQ_printf(m, "\n");
 253 #endif
 254 }
 255 #endif
 256
 257 static inline void timer_list_header(struct seq_file *m, u64 now)
 258 {
 259         SEQ_printf(m, "Timer List Version: v0.9\n");
 260         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 261         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 262         SEQ_printf(m, "\n");
 263 }
 264
 265 void sysrq_timer_list_show(void)
 266 {
 267         u64 now = ktime_to_ns(ktime_get());
 268         int cpu;
 269
 270         timer_list_header(NULL, now);
 271
 272         for_each_online_cpu(cpu)
 273                 print_cpu(NULL, cpu, now);
 274
 275 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 276         timer_list_show_tickdevices_header(NULL);
 277         for_each_online_cpu(cpu)
 278                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 279 #endif
 280         return;
 281 }
 282
 283 #ifdef CONFIG_PROC_FS
 284 static int timer_list_show(struct seq_file *m, void *v)
 285 {
 286         struct timer_list_iter *iter = v;
 287
 288         if (iter->cpu == -1 && !iter->second_pass)
 289                 timer_list_header(m, iter->now);
 290         else if (!iter->second_pass)
 291                 print_cpu(m, iter->cpu, iter->now);
 292 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 293         else if (iter->cpu == -1 && iter->second_pass)
 294                 timer_list_show_tickdevices_header(m);
 295         else
 296                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 297 #endif
 298         return 0;
 299 }
 300
 301 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 302 {
 303         for (; offset; offset--) {
 304                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 305                 if (iter->cpu >= nr_cpu_ids) {
 306 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 307                         if (!iter->second_pass) {
 308                                 iter->cpu = -1;
 309                                 iter->second_pass = true;
 310                         } else
 311                                 return NULL;
 312 #else
 313                         return NULL;
 314 #endif
 315                 }
 316         }
 317         return iter;
 318 }
 319
 320 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 321 {
 322         struct timer_list_iter *iter = file->private;
 323
 324         if (!*offset)
 325                 iter->now = ktime_to_ns(ktime_get());
 326         iter->cpu = -1;
 327         iter->second_pass = false;
 328         return move_iter(iter, *offset);
 329 }
 330
 331 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 332 {
 333         struct timer_list_iter *iter = file->private;
 334         ++*offset;
 335         return move_iter(iter, 1);
 336 }
 337
 338 static void timer_list_stop(struct seq_file *seq, void *v)
 339 {
 340 }
 341
 342 static const struct seq_operations timer_list_sops = {
 343         .start = timer_list_start,
 344         .next = timer_list_next,
 345         .stop = timer_list_stop,
 346         .show = timer_list_show,
 347 };
 348
 349 static int __init init_timer_list_procfs(void)
 350 {
 351         struct proc_dir_entry *pe;
 352
 353         pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
 354                         sizeof(struct timer_list_iter), NULL);
 355         if (!pe)
 356                 return -ENOMEM;
 357         return 0;
 358 }
 359 __initcall(init_timer_list_procfs);
 360 #endif